1.1 Field of the Technology
The present technology relates to methods and systems for manufacturing/sizing patient interfaces, such as masks for respiratory therapy devices, such as by assessing facial details for such masks. More particularly, the technology concerns digital scanning of feature of person's face for such patient interfaces. The present technology also relates to the preparation and design of a patient interface, such as a mask, based on a digital scan of a person's face.
1.2 Description of the Related Art
A range of respiratory disorders exist, e.g., Obstructive Sleep Apnea (OSA), Cheyne-Stokes Respiration (CSR), Obesity Hyperventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease (COPD), Neuromuscular Disease (NMD), chest wall disorders, etc. These disorders may be characterized by particular events, e.g. apneas, hypopneas, and hyperpneas, and may be treated or prevented using a range of therapies. Such therapies include, for example, Continuous Positive Airway Pressure (CPAP) therapy to treat OSA, and Non-invasive ventilation (NIV) to treat CSR, OHS, COPD, MD and chest wall disorders. These therapies may be provided by a treatment system or device, including respiratory equipment to provide a range of ventilatory support to patients, including full ventilatory support, assisting the patient in taking a full breath, and/or maintaining adequate oxygen levels in the body by doing some or all of the work of breathing.
1.2.1 Patient Interface
A patient interface may be used to interface respiratory equipment to its wearer, for example by providing a flow of air to an entrance to the airways. The flow of air may be provided via a mask to the nose and/or mouth, a tube to the mouth or a tracheostomy tube to the trachea of a patient. Depending upon the therapy to be applied, the patient interface may form a seal, e.g., with a region of the patient's face, to facilitate the delivery of gas at a pressure at sufficient variance with ambient pressure to effect therapy, e.g., at a positive pressure of about 10 cmH2O relative to ambient pressure. For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10 cmH2O.
The design of a patient interface presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of noses varies considerably between individuals. Since the head includes bone, cartilage and soft tissue, different regions of the face respond differently to mechanical forces. The jaw or mandible may move relative to other bones of the skull. The whole head may move during the course of a period of respiratory therapy. FIGS. 1A-1F depict several facial features and anthropomorphic measurements that are subject to variation between individuals. Several of the depicted features are described in greater detail in the glossary below, specifically in the section titled “Anatomy of the Face.”
As a consequence of these challenges, some masks suffer from being one or more of obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and uncomfortable especially when worn for long periods of time or when a patient is unfamiliar with a system. For example, masks designed solely for aviators, masks designed as part of personal protection equipment (e.g. filter masks), SCUBA masks, or for the administration of anesthetics may be tolerable for their original application, but nevertheless such masks may be undesirably uncomfortable to be worn for extended periods of time, e.g., several hours. This discomfort may lead to a reduction in patient compliance with therapy. This is even more so if the mask is to be worn during sleep.
CPAP therapy is highly effective to treat certain respiratory disorders, provided patients comply with therapy. If a mask is uncomfortable, or difficult to use a patient may not comply with therapy. Since it is often recommended that a patient regularly wash their mask, if a mask is difficult to clean (e.g., difficult to assemble or disassemble), patients may not clean their mask and this may impact on patient compliance.
While a mask for other applications (e.g. aviators) may not be suitable for use in treating sleep disordered breathing, a mask designed for use in treating sleep disordered breathing may be suitable for other applications.
For these reasons, patient interfaces for delivery of CPAP during sleep form a distinct field
1.2.2 Custom Design of Patient Interface
In order to design a patient interface that provides effective treatment and is comfortable for the user to wear, it is desirable to customize the shape of the patient interface, particularly the mask of the patient interface, to conform with the three-dimensional shape of the user's face. In other to provide such customization, it is often necessary to collect information about the shape of the user's face. This is particularly significant where a seal with the patient's face is necessary for providing an effective respiratory treatment, such as in the application of positive pressure therapy. Moreover, comfort increases patient compliance with therapy.
One way of collecting information about the shape of a user's face is to take a three-dimensional scan of the user's face or head. The three-dimensional scan would include all of the complexities of the user's face. Thus, a patient interface designed based on the three-dimensional scan would be specially designed to conform to the specific contours of the user's face.
A drawback of using a three-dimensional scan is that the equipment used for taking the scan may not be readily available to the user. This means that the user may need to acquire the equipment, which may be expensive. Alternatively, the user may need to schedule an appointment with and travel to a facility that has the equipment. Such scheduling and travel may be inconvenient for the user, and may dissuade the user from obtaining a customized patient interface. Additionally, the user and/or patient interface designer will need to factor the facility's scanning services into the cost of producing the patient interface for the user. Thus, use of three-dimensional scanning technology may add an unwanted cost to the production process. These factors may in turn dissuade the user from ordering a customized patient interface, which in turn (for the reasons explained above) may adversely affect user compliance with therapy or provision of the most effective therapy.
The above drawbacks have been described in the specific context of designing and manufacturing customized patient interfaces and masks, for instance for an individual suffering from a respiratory condition, the same drawbacks and challenges apply to designing and manufacturing any article, apparatus or other apparel that may be worn on a person's head or face. For instance, if a user wishes to order custom-fit sunglasses, goggles, a face mask, or costume, the user may be inconvenienced to have to pay and/or travel in order to have a scan of their face taken.
Accordingly, there is a need for a method and system that collects information about the three-dimensional characteristics of the user's face without the unwanted inconvenience or cost associated with presently known three-dimensional scanning technology and infrastructure.